Process of treating metal-bearing materials.



UNITED err s re s PATENT OFFICE.

cuisine W. MERRILL, or LEAD, sou'rn DAKOTA PROCESS OF TREATINGMETAL-BEARING MATERIALS.

Specification of Letters Patent.

Patented May 1 5, 1906.

Application lllcd July 7. 1906. Berisl No. 268.?29-

10 all whom it may concern: 7

Be it known that 1, CHARLES W. MERRILL, a citizen of the United States,and a resident of Lead, Lawrence county, State of South Dakota, haveinvented a new and usefuLImpro'vement in Processes for TreatingPrecious-Metal-Bearin Materials, of which the following is a specication.

My invention relates to an improvement in the art of treatingreciousmetal-bearing materials, particular y those ores or taili s whichcontain reducing salts or minera s with cyanogen-bearin solutions.

I have heretofore o tained or applied for Letters Patent forimprovements in treating that, class of-ores and tailings which containreducing salts or minerals with solutions of perfected alkali-metal canids by filling the interstitial spaces wit an oxidizing agent prelimianary 'tocontact with a cyanid solution. Now Ihave discovered that ifafter the first contact with the cyanogen-bearing solutions the cyanidsolution is Withdrawn and the interstitial spaces filled. with anoxidizing agent under pressure greater than that of the atmosphere in aclosed container and then again sub'ected to the treatment with thecyanogencaring solution the yield is often increased. y

As is well known, all methods of crushing ore are divided, generallyspeaking, into What is known as wet crushing and dry crush the formernecessitating the presence of 1 uidin the material. The efi'ect of theliqui being present with the mixed ore is merely incident to theoperation and not essential and hence in the various processes by meprior. to effecting oxidation the liquid is removed from theinterstitial spaces of the mass by draining the containers of thefilter-pres'ses'in which the same are collected in any convenientmanner, after which the interstitial spaces are filled with theoxidizing agent, and the contact thus formed between. the finely-dividedmetalbearing material and the oxidizing agent is maintained until partor all of the reducing material has'been oxidized. This oxidation, in mypreviously patented processes has been effected by the introduction ofatmospheric air or other oxidizing a out under rcssure or a solution ofa hypoc lorite preiminary to the first contact with the c anidsolutions, and the effect of the oxi izing agent upon the reducingsubstance is very other similar oxidizing agent under ressure muchgreater, for the reason that in this manner an envelop of oxidizingagent isformed around the particles of solid matter and the said contactor envelop is maintained and re-. newed when necessary until part or allof the reducing material has been oxidized, after which the air or otheroxidizin agent is then displaced and thecyanogencaring solution isintroduced. Notwithstandin this preliminary oxidation, in some cases anin other cases where preliminary oxidation may be inadvisable 1 hnd itadvantageous to introduce into the interstitial spaces of the mass inthe closed container a cyanogenbearin solution, and after the firstcontact with t e solution the latter is removed from the interstitialspaces of the crushed ore in the container by draining or otherwise. I

then cause a solution of a hypochlorite or to be introduced into. theinterstitia spaces of the mass inthe closed container for the urose ofoxidizing all such particles of re noin material as may be therepresent. After this the air or other oxidizing. agent is then 80displaced, and the particles within the container are subjected tofurther treatment with'a cyanogen-bearing solution. For the purpose ofefiecting oxidation 1 emplo as in my previous processes, an alkali metaoralkaline earth metal hypochlorite, such as by poehlorite of calcium,and this hy ochlorite mixed with chlorite of calcium in e form ofbleaching-powder, which is obtainable in suflicient quantities at lowcost, is effective for the purpose, or a gaseous oxidizing agent underpressure, such as com ressed air. The recess is conducte in any closedform 0 container, to which the oxidizing agent under ressure me beapplied after removal of tile liquid, w on there present, from theinterstitial spaces of the crushed ore contained therein, the effect ofsuch aplication being to provide an envelop of oxidizing agent aroundeach particle of the I00 crushed ore under a pressure greater than thatof the atmosphere, which is only possible in closed containers.

I claim as my invention-- 1. The improvement in treating a precious- I o5 metal-bearing material with cyanogen-bearingsolutions in a closedcontainer after preliminary contact with such solution consisting inremoving t e cyano en-bearing solutions from the lnterstitia spaces ofthe no crushed material, applying an oxidizing agent under pressuregreater than that of the atmos here to said material, and subsequent yapplying a cyanogen-bearing solut1on to said material.

2. The improvement in treating a preciousmetal-bearing material withcyanogen-bearing solutions in a closed contalner after pre liminarycontact with such solution consisting in removing the cyanogen-bearingsolutions from the interstitial spaces of the crushed material ap lying"air under pressure greater than that oi the atmosphere to said materialand subsequently a plying a cyanogen-bearing solutlon to sai material.

-3. The improvement in treatingapreciousmetal-bearing material withcyanogen-bearing solutions in a closed container after preliminarycontact with such solution consisting in removing the eyano en-bearingsolu tions from the interstitia spaces of the crushed material ap lyingair under pressure greater than that 0? the atmosphere to said materialand subsequently applying a cymetal-bearing material containingreducingagents with cyanogen-bearing solutionsconslsting in firstcollecting the crushed material in a closed container, applying a c anoenbearing solution to said materlafsu sequently removing saidcyanogen-bearin solution from the interstitial spaces of said material,applying air under pressure greater than that of the atmosphere, andsubsequently ap lying a cyanogen-bearing solut1on to sai materialin oneand the same closed container.

In testimon that I claim the foregoing as my invention havesignedmyname,in resence of two witnesses, this 22d day of ay 1905. i

CHARLES W. MERRILL.

Witnesses:

ANsoN T. BLAKE, H. E, JOHNSTON.

